Add simple test

src/test/groovy/org/sonarqube/gradle/FunctionalTests.groovy

@@ -21,6 +21,7 @@ package org.sonarqube.gradle
 
 
 import org.gradle.testkit.runner.GradleRunner
+import org.gradle.testkit.runner.UnexpectedBuildFailure
 import spock.lang.Specification
 import spock.lang.TempDir
 
@@ -548,4 +549,28 @@ class FunctionalTests extends Specification {
         testSources[0].endsWith("""$projectDir/integrationTests/run-all.sh""")
         testSources[1].endsWith("""$projectDir/test-license.sh""")
     }
+
+    def "task fails with an IllegalStateException when failing to reach the server"() {
+        given:
+        settingsFile << "rootProject.name = 'java-task-toolchains'"
+        buildFile << """
+        plugins {
+            id 'org.sonarqube'
+        }
+        """
+
+        when:
+        GradleRunner.create()
+                .withProjectDir(projectDir.toFile())
+                .forwardOutput()
+                .withArguments('sonar', '-Dsonar.host.url=http://localhost:0')
+                .withPluginClasspath()
+                .build()
+
+        then:
+        def exception = thrown(RuntimeException.class)
+        assert exception instanceof UnexpectedBuildFailure
+        // The cause of the issue is not reported here but we can find it in the error message
+        assert exception.message.contains("java.lang.IllegalStateException: Failed to get server version")
+    }
 }